Meningitis

Meningitis is always cerebrospinal infection. Meningitis is a rare infection that affects the delicate membranes -- called meninges -- that cover the brain and spinal cord.There are several types of this disease, including bacterial, viral, and fungal.

1. Meningitis Prepared by, ARATHY R NATH

2. An inflammation of the meninges , the thin lining surrounding the brain and the spinal cord. Meningitis is usually caused by bacteria or viruses, but can be a result of injury, cancer, or certain drugs. Main focus on bacterial meningitis due to Neisseria meningitidis ( meningococcus ); causes large scale epidemics.

3. TRANSMISSION Transmission is person to person from respiratory droplet/throat secretions d uring close and prolonged contact with carrier or sick untreated person. No animal reservoirs . Incubation : 4 days in average (range is 2-10 days). Bacteria sometimes overwhelms the body’s defenses allowing infection to spread through the bloodstream and to the brain.

4. Asymptomatic carriers : -bacteria in the pharynx (throat ) unaffected by the disease themselves -can transmit it to others - prevalence : 1-10% (endemic situations), 10-25% ( epidemics ).

5. CLASSIFICATION Infectious meningitis is broadly classified into 3 groups: A cute Pyrogenic ( BACTERIAL ) Meningitis Aseptic (usually acute VIRAL ) Meningitis Chronic ( usually TUBERCULOUS/ FUNGAL ) Meningitis

6. CAUSATIVE AGENTS OF MENINGITIS

7. BACTERIAL AGENTS NEONATAL : E.Coli Group B Streptococci INFANTS : Hemophilus Influenzae ADOLESCENTS : Niesseria meningitidis ( most common) Streptococcus pneumoniae ELDERLY : Listeria monocytogens Streptococcus pneumoniae 2) VIRAL AGENTS Enterovirus (most common) Mumps virus Coxsackie virus HSVII EBV

8. 3)   FUNGAL AGENTS : Candida albicans , Cryptococcus neoformans Blastomyces dermatidis Coccidiodesimitis   4) PARASITES Protozoa Nematodes Cestodes

9. ROUTES OF INFECTION There are 4 methods by which microbes enter the nervous system   Hematogenous route : through arterial and venous spread; is the most common route of entry Direct implantation : it may be traumatic or rarely iatrogenic i.e. through a lumbar puncture needle Local extension : through air sinuses, infected tooth or a surgical site . Through peripheral nervous system : as occurs with certain viruses.

10. Meningitis is usually caused by bacteria or viruses, but can be a result of injury, cancer, or certain drugs. BACTERIAL MENINGITIS Also known as septic meningitis Extremely serious that requires immediate care Can lead to permanent damage of brain or disability and death. Spreads by : coughing and sneezing. Vaccines are available to help protect against some kinds of bacterial meningitis .

11. Pathophysiology Bacteria enters blood stream/ trauma Enters the mucosal surface/ cavity Breakdown of normal barriers Crosses the blood brain barrier Proliferates in the CSF Inflammation of the meninges Increase in ICP

12. Risk factors Certain people are at increased risk for bacterial meningitis. Some risk factors include: Age Babies are at increased risk for bacterial meningitis compared to people in other age groups. However , people of any age can develop bacterial meningitis. See section above for which bacteria more commonly affect which age groups . 2) Community setting Infectious diseases tend to spread where large groups of people gather together. College campuses have reported outbreaks of meningococcal disease, caused by  N . meningitidis .

13. 3) Certain medical conditions There are certain medical conditions, medications, and surgical procedures that put people at increased risk for meningitis. 4 ) Working with meningitis-causing pathogen Microbiologists routinely exposed to meningitis-causing bacteria are at increased risk for meningitis.

14. 5) Travel Travelers may be at increased risk for meningococcal disease, caused by N. meningitidis , if they travel to certain places, such as: The meningitis belt in sub-Saharan Africa, particularly during the dry season Mecca during the annual Hajj and Umrah pilgrimage

15. Clinical manifestation Fever Severe headache Nausea and vomiting Nuchal rigidity Positive Kerning’s sign Positive Brudzinski’s sign Photophobia A decreased level of consciousness Signs of increase ICP Coma

16. Complications Waterhouse- Friderichsen syndrome obstructive hydrocephalus chronic adhesive arachnoiditis focal cerebritis   P hlebitis leading to venous occlusion and hemorrage of underlying brain .

17. 2) Viral meningitis Meningitis caused by viruses is called ‘viral meningitis’.  It  is relatively common.  Most  cases of viral meningitis are mild. Some people may  be hospitalised  for a short time.  On  rare occasions viral meningitis can be life threatening.  It  can be caused by various different viruses and is often a complication of another viral illness.

18. 3) Chronic meningitis Slow-growing organisms (such as fungi and Mycobacterium tuberculosis) that invade the membranes and fluid surrounding your brain cause chronic meningitis. Chronic meningitis develops over two weeks or more . The symptoms of chronic meningitis — headaches, fever, vomiting and mental cloudiness — are similar to those of acute meningitis.

19. 4) Fungal meningitis Fungal meningitis is relatively uncommon and causes chronic meningitis. It may mimic acute bacterial meningitis. Fungal meningitis isn't contagious from person to person. Cryptococcal meningitis is a common fungal form of the disease that affects people with immune deficiencies, such as AIDS. It's life-threatening if not treated with an antifungal medication.

20. 5) Other meningitis causes Meningitis can also result from noninfectious causes, such as chemical reactions, drug allergies, some types of cancer and inflammatory diseases such as sarcoidosis .

21. Diagnostic evaluation By + ve signs Physical examination History collection CSF evaluation for pressure, proteins, glucose and leukocytes. Blood test CBC Blood culture MRI CT scan 

22. MANAGEMENT

23. Treatment of meningitis include : Specific treatment Treatment is started with antibiotic, commonly used antibiotics are ( Cephalosporins , vancomycin , cefotaxine ) for 7-14 days & 3 weeks for gram – ve bacteria. b) Symptomatic treatment Seizure management: phenobarbitone , Dilantin & Diazepam Management of intracranial pressure: Mannitol , Frusemide Fever and headache: Aspirin or acetaminophen

24. PREVENTION Some forms of bacterial meningitis can be prevented by  vaccination Haemophilus   influenzae  type b  Hib  vaccine is recommended  apart  of the  National Immunization  Program and is available free for  all children at 6 weeks , 4 months, 6 months and 12 months of age and is administered in a combination vaccine. Meningococcal a vaccine is available for the meningococcal B strain;  howeverthis  vaccine is not currently on the National  Immunisation   Schedule, more inofrmation visit your GP or immunisation provider.